Direct polysulfone

Although the substitution of a preformed phthalocyanine always leads to a complex mixture of more- or less-substituted products, the reaction is of major industrial importance. Besides the chloro- and bromocopper phthalocyanines, also polysulfonated phthalocyanines, which are used as water-soluble dyes, are produced by the reaction of copper phthalocyanine with the respective reactant. While typical aromatic reactions of the Friedel-Crafts type are also possible,333 direct nitration of the macrocycle commonly results in oxidation of the phthalocyanine. However, under mild conditions it is possible to introduce the nitro group directly into several phthalocyanines.334... 

Recendy, Guiver et al. reported a number of derivatives of polysulfone and poly(aryl sulfone).172 188 Polysulfones were activated either on the ortho-sulfone sites or the ortho-ether sites by direct lithiation or bromination-lithiation. The lithiated intermediates were claimed to be quantitatively converted to azides by treatment with tosyl azides. Azides are thermally and photochemically labile groups capable of being transformed readily into a number of other useful derivatives. 

Direct fluorination of polymer or polymer membrane surfaces creates a thin layer of partially fluorinated material on the polymer surface. This procedure dramatically changes the permeation rate of gas molecules through polymers. Several publications in collaboration with Professor D. R. Paul62-66 have investigated the gas permeabilities of surface fluorination of low-density polyethylene, polysulfone, poly(4-methyl-1 -pentene), and poly(phenylene oxide) membranes. 

To date, much effort has been undertaken to develop new alternatives. For example, sulfonated aromatic polymers, i.e., polymers with the sulfonic acid groups directly attached to the main chain or carrying short pendant side chains with terminal sulfonic acid units, attract increasing interest because of their chemical and thermal stability, and the ease of the sulfonation procedure. Some of the proposed polymers are sulfonated polysulfone (SPSU) [134] sulfonated poly(phenylene oxide) (SPPO) [135] sulfonated poly-(ether ether ketone) (SPEEK) [136] poly(phenylquinoxaline) (PPQ) [137] and poly(benzeneimidazole) (PBI) [138],... 

Manea, C. and Mulder, M. 2002. Characterization of polymer blends of poly-ethersulfone/sulfonated polysulfone and polyethersulfone/sulfonated poly-etheretherketone for direct methanol fuel cell applications. Journal of Membrane Science 206 443-453. 

Similarly, polysulfone has been sulfophenylated by lithiation and anionic reaction with 2-sulfobenzoic acid cyclic anhydride (Figure 12). This provides another method to modify polysulfones by attaching pendant sulfonated phenyl groups via ketone links. It would be interesting to see if the phase separation in these materials was affected by the additional functionality of the ketone or the pendant attachment of the sulfonic acid, as opposed to direct attachment of ionic groups to the aromatic polymer backbone. 

Figure 12. Cross-section of the surface zone of a polysulfone hollow fiber (spun from DMF directly into water while conducting nitrogen through the lumen)...

The discussion directly following Eq (6) provides a simple, physically reasonable explanation for the preceding observations of marked concentration dependence of Deff(C) at relatively low concentrations. Clearly, at some point, the assumption of concentration independence of Dp and in Eq (6) will fail however, for our work with "conditioned" polymers at CO2 pressures below 300 psi, such effects appear to be negligible. Due to the concave shape of the sorption isotherm, even at a CO2 pressure of 10 atm, there will still be less than one CO2 molecule per twenty PET repeat units at 35°C. Stern (26) has described a generalized form of the dual mode transport model that permits handling situations in which non-constancy of Dp and Dh manifest themselves. It is reasonable to assume that the next generation of gas separation membrane polymers will be even more resistant to plasticization than polysulfone, and cellulose acetate, so the assumption of constancy of these transport parameters will be even more firmly justified. 

We examined the condensation of disulfonyl chlorides with diphenols, using aliphatic tertiary amines as acid acceptors and found that polysulfonates and copolymers could be obtained readily. This method, as described in our soon-to-be-issued U. S. patent, is directly applicable to the preparation of a wide variety of sulfur-containing polyesters. 

The MF membranes are usually made from natural or synthetic polymers such as cellulose acetate (CA), polyvinylidene difiuoride, polyamides, polysulfone, polycarbonate, polypropylene, and polytetrafiuoroethylene (FIFE) (13). Some of the newer MF membranes are ceramic membranes based on alumina, membranes formed during the anodizing of aluminium, and carbon membrane. Glass is being used as a membrane material. Zirconium oxide can also be deposited onto a porous carbon tube. Sintered metal membranes are fabricated from stainless steel, silver, gold, platinum, and nickel, in disks and tubes. The properties of membrane materials are directly reflected in their end applications. Some criteria for their selection are mechanical strength, temperature resistance, chemical compatibility, hydrophobility, hydrophilicity, permeability, permselectivity and the cost of membrane material as well as manufacturing process. 

The polysulfone membrane allows for protein and toxin transport across the membrane while preventing the passage of foreign cells into the patient. Thus, hepa-tocytes in the device do not have to be compatible with the host immune system since there is no direct contact. 

Non-celluloslc Membranes. While the development of CA gas permeation membranes can be directly attributed to the development of water desalination membranes, the Invention of modified silicone membranes and polysulfone membranes was more Influenced by the extension of knowledge of transport, sorption and diffusion of gases In polymers (24-27). In principle, rubbery polymers exhibit the highest gas permeabilities at the lowest selectlvitles, and. 

The sulfonation of polyethylene films to produce negatively charged membranes was described above24. While adequate for many uses, these aliphatic polysulfonates lack long-term stability under adverse conditions. To improve performance, attention was directed in recent years to sulfonation of so-called engineering thermoplastics , a class of film-forming polyaromatics with improved mechanical and thermal properties. 

The 1950s also saw the development of two families of plastics — acetal and polycarbonates. Together with nylon, phenoxy, polyimide, poly(phenylene oxide), and polysulfone they belong to the group of plastics known as the engineering thermoplastics. They have outstanding impact strength and thermal and dimensional stability — properties that place them in direct competition with more conventional materials like metals. 

Processes developed for the injection molding of circuit boards include PCK Technology s mold-n-plate process uses two shots, the first being one of catalytic resins, to form paths on plastic parts that are then processed in a copper bath to form circuitry. Special grades of polysulfone, polyethersulfone, and polyarylsulfone are used for the process. In the in-mold metallization process, various conductive, resistive, capacitive, or inductive components are embedded directly into the plastic part in the tool. 

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